Supporting device



FIG. 1 is a perspective view of a supporting device showing our design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a left side, elevational view thereof;

FIG. 5 is a right side, elevational view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof.

The broken lines in the figures are for the purpose of illustrating environmental structures that form no part of the claimed design. 

The ornamental design for a supporting device, as shown and described. 